Yakovlev served as editor of several party publications and rose to the key position of head of the CPSU's Department of Ideology and Propaganda from 1969 to 1973. In 1972 he took a bold stand by publishing the article entitled Against Antihistoricism[4] critical of Russian nationalism and nationalism in the USSR in general. As a result he was removed from his position and appointed as ambassador to Canada remaining at that post for a decade.[3]

In 1983, Yakovlev accompanied Mikhail Gorbachev, who at the time was the Soviet official in charge of agriculture, on his tour of Canada. The purpose of the visit was to tour Canadian farms and agricultural institutions in the hopes of taking lessons that could be applied in the Soviet Union; however, the two renewed their earlier friendship and, tentatively at first, began to discuss the prospect of liberalisation in the Soviet Union.

In an interview years later, Yakovlev recalled:

At first we kind of sniffed around each other and our conversations didn't touch on serious issues. And then, verily, history plays tricks on one, we had a lot of time together as guests of then Liberal Minister of AgricultureEugene Whelan in Canada who, himself, was too late for the reception because he was stuck with some striking farmers somewhere. So we took a long walk on that Minister's farm and, as it often happens, both of us suddenly were just kind of flooded and let go. I somehow, for some reason, threw caution to the wind and started telling him about what I considered to be utter stupidities in the area of foreign affairs, especially about those SS-20 missiles that were being stationed in Europe and a lot of other things. And he did the same thing. We were completely frank. He frankly talked about the problems in the internal situation in Russia. He was saying that under these conditions, the conditions of dictatorship and absence of freedom, the country would simply perish. So it was at that time, during our three-hour conversation, almost as if our heads were knocked together, that we poured it all out and during that three-hour conversation we actually came to agreement on all our main points.[5]

In 1987, the Russian chauvinist organization Pamyat sent a letter entitled Stop Yakovlev! to the plenum of the CC of the CPSU, labelling Yakovlev as the main instigator of the course that will lead to the 'capitulation before the imperialists'.[6]

For decades, it was the official policy of the Soviet Union to deny the existence of the secret protocol to the Nazi-Soviet Pact. At the behest of Mikhail Gorbachev, Yakovlev headed a commission investigating the existence of such a protocol. In December 1989 Yakovlev concluded that the protocol had existed and revealed his finds to the Soviet Parliament. As a result, the first multi-party elected Congress of Soviets "passed the declaration admitting the existence of the secret protocols, condemning and denouncing them".[7]

He was promoted to the Politburo in 1987 but by 1990 he had become the focus of attacks by communists in the party opposed to liberalisation. At the 28th Congress of the CPSU in July 1990, a cynical Alexander Lebed caused uproar when he asked Yakovlev: "Alexander Nikolaevich... How many faces have you got?" An embarrassed Yakovlev consulted his colleagues and continued on with the proceedings, ignoring Lebed.[8] As the communists opposed to liberalization gained strength his position became more tenuous, fiercely attacked by his former protégé Gennady Zyuganov in May 1991, he was ultimately removed from the Politburo and was expelled from the Party two days before the August Coup in 1991. During the coup Yakovlev joined the democratic opposition against it. Following the failed coup attempt, Yakovlev blamed Gorbachev for having been naive in bringing the plotters into his inner circle saying Gorbachev was "guilty of forming a team of traitors. Why did he surround himself with people capable of treason?"[9]

In his book Inside the Stalin Archives (2008), Jonathan Brent tells that in 1991, when there were Lithuanian crowds demonstrating for independence from the Soviet Union, Gorbachev consulted Yakovlev about the wisdom of an armed repression against them. Gorbachev asked, "Should we shoot?" Yakovlev answered that, "if a single Soviet soldier fired a single bullet on the unarmed crowds, Soviet power would be over." There were bullets, however, and the USSR collapsed seven months later.[10]

In the years following the dissolution of the Soviet Union, Yakovlev wrote and lectured extensively on history, politics and economics. He acted as the leader of the Russian Party of Social Democracy, which in the mid-1990s fused into United Democrats (a pro-reform alliance that was later reorganized into Union of Rightist Forces). In 2002, acting as head of the Presidential Committee for the Rehabilitation of Victims of Political Repression, he was present at the announcement of the release of a CD detailing names and short biographies of the victims of Soviet purges. In his later life, he founded and led the International Democracy Foundation. He advocated taking responsibility for the past crimes of communism and was critical of President Putin's restrictions on democracy.

In 2000, he publicly alleged that Swedish diplomat Raoul Wallenberg, who became famous for his role in saving thousands of HungarianJews from the Holocaust, was shot and killed in Soviet secret police headquarters in 1947.[citation needed] He was called "God's commie" in a 2002 article for investigating crimes of the Soviet state.[11]

Alexandre Trudeau, son of late Canadian Prime Minister Pierre Trudeau is named for Yakovlev (a family friend of the Trudeaus). The Trudeaus had asked Yakovlev about whether "Sacha" was the nickname for "Alexander".